Humanity Takes Flight: An Exploration Into The Contributions Of David Loye and an Introduction to this Issue of Interdisciplinary Journal of Partnership Studies

This article introduces Volume 9, issue 2 of the Interdisciplinary Journal of Partnership Studies and the issue’s theme of ‘moral sensitivity’ and its connection to the late evolutionary systems scientist and psychologist David Loye. The article will further highlight how Loye came to reconsider and reinterpret Darwin’s work on human evolution, and why this is expressly relevant to navigating the current challenging times we are living through. Additionally, this article will briefly describe the contents of this issue and highlight the diverse collection of contributing authors

Survival, biofilm formation, and growth potential of environmental and enteric escherichia coli strains in drinking water microcosms

E. coli is the most commonly used indicator for faecal contamination in a drinking water distribution system (WDS). The assumption is that E. coli are of enteric origin and cannot persist for long outside their host, therefore acting as indicators of recent contamination events. This study investigates the fate of E. coli in drinking water; specifically addressing survival, biofilm formation under shear stress, and regrowth in a series of laboratory-controlled experiments. We show the extended persistence of three E. coli strains (two enteric and one soil isolate) in sterile and non-sterile drinking water microcosms, at 8 and 17°C, with T90 values ranging from 17.4 ± 1.8 to 149 ± 67.7 days, using standard plate counts and a series of (RT)-Q-PCR assays targeting 16S rRNA, tuf, uidA, and rodA genes and transcripts. Furthermore, each strain was capable of attaching to a surface and replicating to form biofilm in the presence of nutrients under a range of shear stress values (0.6, 2.0, and 4.4 dyn cm-2; BioFlux, Fluxion); however, cell numbers did not increase when drinking water was flowed over (t-test; p > 0.05). Finally, E. coli regrowth within drinking water microcosms containing PE-100 pipe-wall material was not observed in the biofilm or water phase using a combination of culturing and Q-PCR methods for E. coli. The results of this work highlight that when E. coli enters drinking water it has the potential to survive and attach to surfaces but that regrowth within drinking water or biofilm is unlikely

Application of Molecular Markers Derived from \u3cem\u3eMedicago Truncatula\u3c/em\u3e in White Clover (\u3cem\u3eTrifolium Repens\u3c/em\u3e L.)

White clover is the major forage legume of temperate areas. Genome maps have been produced recently (Jones et al., 2003; Barrett et al., 2004) and the location of QTL for important agricultural traits reported (Abberton et al., 2004). White clover is closely related to the model legume Medicago truncatula and there is likely to be considerable benefit in applying genomic resources from model to crop. However, the extent of synteny between the species must be established. Here we present preliminary results detailing progress towards this goal

Mesoscale simulation of stress relaxation in thin polymer films and the connection to nanocomposites

Key insight into interphase formation and confinement effects in nanocomposites has recently come from studies on polymer thin films supported on solid substrates. In these thin films, both the free surface and the solid supporting layer cause complex changes in the behavior of the polymer. The range and magnitude of these effects have been singled out by systematically varying the boundary conditions (free standing film, supported thin film, and polymer layer confined between two surfaces) and surface/polymer chemistry. Most importantly, the Schadler group and the Torkelson group have shown a quantitative equivalence between nanocomposites and thin films with regards to glass-transition temperature (Tg) via the calculation of an equivalent metric of confinement within the nanocomposite from the distribution of filler surface-to-surface distances. This finding is important because it allows for direct prediction of the Tg of the nanocomposite directly from thin film measurements and microstructural statistics, leveraging current capabilities in accurate computational/experimental characterization of film properties. However, it is currently unknown whether the thin-film analogy can be extended into the constitutive behavior of polymer nanocomposites, most importantly the stress relaxation behavior of the matrix that governs viscoelastic behavior. With an ultimate aim to address this issue, we have begun examining the stress-relaxation in doubly supported polymer thin films through coarse grained simulation using the FENE model. The current study elucidates the connection among film thickness, interfacial energy, and stress relaxation dynamics. In order to characterize the dynamic relaxation behavior of the films at constant temperature, we calculate via an extended, tensorial Green–Kubo relation the linear shear-relaxation modulus from equilibrium coarse-grained simulations of the bulk and of films of varying thickness. We then compare the simulated relaxation moduli to both the Rouse model and the theory of Likhtman and McLeish (originally based on the based on the tube model), with the additional changes proposed by Hou, Svaneborg, Everaers, and Grest. Applications to the continuum mechanics of both thin films and nanocomposites will be discussed

Coarse-grained simulation of recovery in thermally activated shape-memory polymers

Thermally actuated shape-memory polymers (SMPs) are capable of being programmed into a temporary shape and then recovering their permanent reference shape upon exposure to heat, which facilitates a phase transition that allows dramatic increase in molecular mobility. Experimental, analytical, and computational studies have established empirical relations of the thermomechanical behavior of SMPs that have been instrumental in device design. However, the underlying mechanisms of the recovery behavior and dependence on polymer microstructure remain to be fully understood for copolymer systems. This presents an opportunity for bottom–up studies through molecular modeling; however, the limited time-scales of atomistic simulations prohibit the study of key performance metrics pertaining to recovery. In order to elucidate the effects of phase fraction, recovery temperature, and deformation temperature on shape recovery, here we investigate the shape-memory behavior in a copolymer model with coarse-grained potentials using a two-phase molecular model that reproduces physical crosslinking. Our simulation protocol allows observation of upwards of 90% strain recovery in some cases, at timescales that are on the order of the timescale of the relevant relaxation mechanism (stress relaxation in the unentangled soft phase). Partial disintegration of the glassy phase during mechanical deformation is found to contribute to irrecoverable strain. Temperature dependence of the recovery indicates nearly full elastic recovery above the trigger temperature, which is near the glass-transition temperature of the rubbery switching matrix. We find that the trigger temperature is also directly correlated with the deformation temperature, indicating that deformation temperature influences the recovery temperatures required to obtain a given amount of shape recovery, until the plateau regions overlap above the transition region. Increasing the fraction of glassy phase results in higher strain recovery at low to intermediate temperatures, a widening of the transition region, and an eventual crossover at high temperatures. Our results corroborate experimental findings on shape-memory behavior and provide new insight into factors governing deformation recovery that can be leveraged in biomaterials design. The established computational methodology can be extended in straightforward ways to investigate the effects of monomer -chemistry, low--molecular-weight solvents, physical and chemical crosslinking, different phase--separation morphologies, and more complicated mechanical deformation toward predictive modeling capabilities for stimuli-responsive -polymers

Breeding White Clover With Improved Tolerance of Nitrogen Fertiliser

White clover (Trifolium repens L.) is often considered a forage legume with a primary use in \u27low input/ low output\u27 systems. One facet of this is the perception that the persistency of this species is poor when Nitrogen (N) fertiliser is applied. However, new varieties of white clover are able to play a significant role in highly productive systems (Williams et al., 2000) and show consistent yields over ten years at a range of applied N levels (Williams et al., 2003). Germplasm improvement for nitrogen tolerance has been carried out with the aim of not only allowing white clover to perform well under applied N but also to dampen the oscillations in clover yield that may be a consequence of the build up of N fixed by the clover itself. The former aspect is illustrated in this paper with respect to the variety AberConcord

Grass and Forage Improvement: Temperate Forages

Key points 1. Plant breeding has contributed significantly to the development of effective grassland production systems. 2. New technologies offer enhanced precision in breeding and access to wider genetic variation. 3. The requirement for more sustainable production systems will require genetic improvements in complex traits where the use of new technology will be vital

Towards a Comparative Map of White Clover (Trifolium Repens) and Barrel Medic (Medicago Truncatula)

Grassland is of pivotal importance to the Irish agricultural industry. This dependence of grass is reflected in the large proportion of land area under grass, approx. 80% of the total land acreage in Ireland. The presence of white clover (Trifolium repens L.) in grassland significantly improves the overall nutritional value of the forage by increasing the relative amounts of nitrogen present. Genetic improvement of white clover through breeding of varieties should increase the productivity of grasslands. Advances in plant biotechnology offer the possibility of developing tools that will radically enhance our ability to breed improved plant varieties. The objective of this study is (1) to construct a genetic map of white clover and (2) to assess the level of genome synteny of white clover and M. truncatula (the model for legume species) with the use of different molecular markers developed in M. truncatula